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tools bpf_jit_disasm: Fix compilation error with new binutils

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binutils changed the signature of init_disassemble_info(), which now causes
compilation to fail for tools/bpf/bpf_jit_disasm.c, e.g. on debian
unstable.

Relevant binutils commit:

  https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=60a3da00bd5407f07

Wire up the feature test and switch to init_disassemble_info_compat(),
which were introduced in prior commits, fixing the compilation failure.

I verified that bpf_jit_disasm can still disassemble bpf programs, both
with the old and new dis-asm.h API. With old binutils there's no change in
output before/after this patch. When comparing the output from old
binutils (2.35) to new bintuils with the patch (upstream snapshot) there
are a few output differences, but they are unrelated to this patch. An
example hunk is:

     f4:	mov    %r14,%rsi
     f7:	mov    %r15,%rdx
     fa:	mov    $0x2a,%ecx
  -  ff:	callq  0xffffffffea8c4988
  +  ff:	call   0xffffffffea8c4988
    104:	test   %rax,%rax
    107:	jge    0x0000000000000110
    109:	xor    %eax,%eax
  - 10b:	jmpq   0x0000000000000073
  + 10b:	jmp    0x0000000000000073
    110:	cmp    $0x16,%rax

However, I had to use an older kernel to generate the bpf_jit_enabled =
2 output, as that has been broken since 5.18 / 1022a5498f ("bpf,
x86_64: Use bpf_jit_binary_pack_alloc").

  https://lore.kernel.org/20220703030210.pmjft7qc2eajzi6c@alap3.anarazel.de

Signed-off-by: Andres Freund <andres@anarazel.de>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Ben Hutchings <benh@debian.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Quentin Monnet <quentin@isovalent.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: bpf@vger.kernel.org
Link: http://lore.kernel.org/lkml/20220622181918.ykrs5rsnmx3og4sv@alap3.anarazel.de
Link: https://lore.kernel.org/r/20220801013834.156015-6-andres@anarazel.de
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Andres Freund 2022-07-31 18:38:31 -07:00 committed by Arnaldo Carvalho de Melo
parent 83aa012048
commit 96ed066054
2 changed files with 8 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
tools/bpf/Makefile
View File

@ -34,7 +34,7 @@ else
endif
FEATURE_USER = .bpf
FEATURE_TESTS = libbfd disassembler-four-args
FEATURE_TESTS = libbfd disassembler-four-args disassembler-init-styled
FEATURE_DISPLAY = libbfd disassembler-four-args
check_feat := 1
@ -56,6 +56,9 @@ endif
ifeq ($(feature-disassembler-four-args), 1)
CFLAGS += -DDISASM_FOUR_ARGS_SIGNATURE
endif
ifeq ($(feature-disassembler-init-styled), 1)
CFLAGS += -DDISASM_INIT_STYLED
endif
$(OUTPUT)%.yacc.c: $(srctree)/tools/bpf/%.y
$(QUIET_BISON)$(YACC) -o $@ -d $<

5
tools/bpf/bpf_jit_disasm.c
View File

@ -28,6 +28,7 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <limits.h>
#include <tools/dis-asm-compat.h>
#define CMD_ACTION_SIZE_BUFFER 10
#define CMD_ACTION_READ_ALL 3
@ -64,7 +65,9 @@ static void get_asm_insns(uint8_t *image, size_t len, int opcodes)
assert(bfdf);
assert(bfd_check_format(bfdf, bfd_object));
init_disassemble_info(&info, stdout, (fprintf_ftype) fprintf);
init_disassemble_info_compat(&info, stdout,
(fprintf_ftype) fprintf,
fprintf_styled);
info.arch = bfd_get_arch(bfdf);
info.mach = bfd_get_mach(bfdf);
info.buffer = image;